Power generation devices, such as a solar or wind power generation devices, are devices designed to create energy. Solar power is generated by transforming solar energy into electricity and is supplied to homes as a natural source of energy. The amount of power generation continuously fluctuates with weather and meteorological conditions.
A heat pump hot water heater heats a refrigerant by absorbing heat from the atmosphere and compressing the refrigerant using electricity, and then transfers the heat to the water via a heat exchanger, thereby creating hot water. With this method, the hot water supply system uses less energy than with an electric hot water heater in which heating is done by an electric heater.
The heat pump hot water supply system which includes the power generation device constitutes a combination of the above devices, and supplies a consumer with power and heat. An example of a conventional heat pump hot water supply and heating system which includes a power generation device is disclosed in PTL 1.
PTL 1 discloses an invention which obtains weather forecast information from a server using a weather information obtaining unit, and switches to use solar generated power to boil the water in the CO2 heat pump hot water heater instead of late night power from a commercial power source when the obtained information is set up as a condition for operation. Operating using power harnessed from natural energy allows for a power efficient, low-energy electric hot water heater which can reduce electricity costs.